Silicon nitride etching composition and method

ABSTRACT

Compositions useful for the selective removal of silicon nitride materials relative to polysilicon, silicon oxide materials and/or silicide materials from a microelectronic device having same thereon are provided. The compositions of the invention are particularly useful in the etching of 3D NAND structures.

FIELD OF THE INVENTION

The present invention relates to a composition and method forselectively etching silicon nitride in the presence of silicon oxide,polysilicon and/or metal silicides, and more particularly to acomposition and method for effectively and efficiently etching a layerof silicon nitride at a high etch rate and with high selectivity withrespect to exposed or underlying layers of silicon oxide, polysiliconand/or metal silicides, particularly in a multilayer semiconductor waferstructure.

BACKGROUND OF THE INVENTION

There is a continued need for improved microelectronic deviceperformance there is a continued emphasis on decreasing devicedimensions, which provides the dual advantages of dramaticallyincreasing device density as well as improving device performance.Device performance is improved because decreased device dimensionsresult in shorter paths that need to be traveled by charge carriers,e.g., electrons.

For example, Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFET)gate electrodes have as electrical points of contact the gate surfaceand the source and drain regions. The distance between the source anddrain regions forms the channel length of the gate electrode, and assuch, by decreasing device dimensions the channel length isconcomitantly decreased. The result is that the switching speed of thedevice is increased.

It is self-evident that reducing device dimensions results in increasedpackaging density of devices on a microelectronic device chip. Thisincreased packaging density brings with it sharp reductions in thelength of the interconnect paths between devices, which reduces therelative negative impact (such as resistive voltage drop, cross talk orRC delay) that these interconnect paths have on overall deviceperformance.

Such requirements however cause problems of increased parasiticcapacitance, device contact resistance (gate, source and drain contactsin MOSFET devices), and tight tolerance of pattern definition. For verysmall sub-micron or sub-half-micron or even sub-quarter-micron modernsilicon devices, the conventional photolithographic technique forpatterning contacts will not meet the required tolerance of criticaldimensions. Methods that have been explored to improve resolution andfeature size include the formation of a self-aligned poly-silicon(poly-Si) gate structure, which helps to solve the problem of criticaldimension tolerance. Using this method, the contact points that areformed for the source and the drain of the gate electrode self-alignwith the poly-Si gate.

One problem encountered during the formation of self-aligned gatestructures has been the selective removal of silicon nitride materialsrelative to polysilicon, silicon oxide and/or metal silicide materials.For example, during the anisotropic etching of the silicon nitride layercovering the gate electrodes, the underlying silicon oxide layer andsilicon substrate are often damaged as well, causing a deterioratedreliability of a semiconductor device.

Conventional wet etching techniques for selectively removing siliconnitride (Si₃N₄) have utilized hot (approximately 145-180° C.) phosphoricacid (H₃PO₄) solutions with water, typically 85% phosphoric acid and 15%water (by volume). Using fresh hot phosphoric acid, the typicalSi₃N₄:SiO₂ selectivity is about 40:1. Advantageously, as the nitridelayer is removed, hydrated silicon oxide forms, which consistent with LeChatelier's principle, inhibits the additional removal of silicon oxidefrom the device surface; thus selectivity gradually increases with use.Disadvantages associated with the use of hot phosphoric acid etchesinclude the corrosion of metal silicide materials, e.g., gate contactmaterials, the etching of silicon oxide, and process control due to thedifficultly associated with maintaining a specific amount of water inthe process solution. In addition, hot phosphoric acid has been adifficult medium to adapt to single wafer tools, which have becomeincreasingly preferred by many manufacturers.

Another way to selectively remove silicon nitride includes the use of acomposition including hydrofluoric acid, however, said compositions alsoremove silicon oxides. A Si₃N₄:SiO₂ selectivity of about 10:1 can beachieved through dilution; however, the etch rate of silicon nitride iscompromised or above-ambient pressure must be used. Still anotherprocess to remove silicon nitride includes the dry etch removal usinghalogenated gaseous species; however, the Si₃N₄:Si₂ selectivity ratio iseven worse than that obtained using the aforementioned wet etchprocesses.

3D-NAND structures in development today at all the major memory chipmanufacturers require high-selectivity etching of silicon nitride (SiN)out of high aspect ratio “slits” defined by oxide (PETEOS). In theregular hot phosphoric acid “hot phos” process the selectivity iscontrolled by pre-dissolving a certain amount of nitride. The dissolvedsilicon nitride is converted into slightly soluble oxide; the samehappens during etching, but the oxide soon starts depositing near theslits' openings, eventually blocking them. See also US 2017/0287725, inparticular FIG. 1D, which shows an illustration where the deposition ofcolloidal silica tends to “pinch off” the gaps or trenches in themicroelectronic device. As a result, the process window of pre-etchoxide concentration is very narrow, difficult to control, and the etchbath has to be replaced very often. Oxide re-deposition rate thus needsto be minimized.

In addition, the deep slits take a long time to etch (typically ≥1 hr).Addition of HF in small amounts increases etch rates, but alsopolymerization of soluble silica species and consequently oxidere-deposition rates. Furthermore, the volatility of HF and relatedfluorinated species causes process control difficulties.

In planar NAND technology, scaling is driven mostly by lithography. Inscaling 3D NAND, extreme precision and process repeatability is requiredto create complex 3D structures with very high-aspect-ratio (HAR)features. Therefore, achieving success with 3D NAND requires innovativepatterning solutions that minimize variability. (See OvercomingChallenges in 3D NAND Volume Manufacturing. Solid State Technologywebsite:http://electroig.com/blog/2017/07/overcoming-challenges-in-3d-nand-volume-manufacturing/)

Precision in etching extreme HAR features is critical for optimizingchannel holes and trenches for cell access, as well as its uniquestaircase structure architecture, which connects the cells tosurrounding CMOS circuitry for reading, writing, and erasing data. Ifthe vertical pitch of the memory stack is around 50 nm, then a 96 layerstack is on the order of 4.8 μm high. This corresponds to a challengingaspect ratio of ˜100:1.

Additionally, as multilayer stack heights increase, so does thedifficulty in achieving consistent etch and deposition profiles at thetop and the bottom of the memory array. For example, given a ratio of˜100:1, the selective removal of Si₃N₄ in the memory stack becomes awet-etch challenge. The difficulty is removing the Si₃N₄ consistently atthe top and the bottom of the stack and across the wafer, withoutetching any of the Sift. Below 96 layers, this task is performed usinghot phosphoric acid (˜160° C.); however, at 96 layers and above, aspecially formulated wet etch chemistry is needed to improve processmargin.

SUMMARY OF THE INVENTION

In one aspect, the invention provides compositions useful in etching asubstrate having a surface comprising silicon nitride and silicon oxide,with selectivity for etching the silicon nitride relative to the siliconoxide. The composition comprises phosphoric acid, at least one silanecompound chosen from alkylamino alkoxy silanes and alkylamino hydroxylsilanes, a solvent comprising water, and optionally a fluoride compound.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-4 show a comparison of several examples of the invention interms of etch rates versus Si loading. Silicon nitride and silicon oxideetch rates were measured using CVD silicon nitride films and PECVDsilicon oxide films. Silicon oxide films were exposed to the etchingformulation for 4 hours so that the small amount of film loss could bemeasured. Silicon nitride films were etched for 5 minutes and 10minutes. Film thicknesses were measured before and after processing byspectroscopic ellipsometry and these thicknesses were used to calculateetch rates.

Specifically, the figures depicts the following:

FIG. 1 depicts a graph that shows etch rates as a function of Si Loading

FIG. 2 depicts a graph displaying the etch rates as a function of Siloading

FIG. 3 depicts graph displaying the etch rates in 85% phosphoric acid asa function of Si loading

FIG. 4 depicts a graph showing selectivity (“example B”), (“example A”)and 85% H₃PO₄.

FIG. 5 shows schematically a structure of an exemplary substrate asdescribed, before and after a selective etching step as also described.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the present invention relates to compositions which areuseful in the selective removal of silicon nitride relative topolysilicon (poly-Si) and silicon oxide material deposited from asilicon oxide precursor source, and hence are useful as wet etchants forat least partial removal of silicon nitride material from amicroelectronic device. Metal silicide materials that may be presentshould not be substantially corroded by said removal compositions.

The invention also provides methods, processes, and systems for usingthe wet etching compositions to remove silicon nitride from a substratecontaining silicon nitride and silicon oxide. The compositions canproduce an advantageously high etch rate of silicon nitride, anadvantageously high selectivity of silicon nitride relative to siliconoxide, or an advantageous balance of these performance properties.

For ease of reference, “microelectronic device” corresponds tosemiconductor substrates, including 3D NAND structures, flat paneldisplays, and microelectromechanical systems (MEMS), manufactured foruse in microelectronic, integrated circuit, or computer chipapplications. It is to be understood that the term “microelectronicdevice” is not meant to be limiting in any way and includes anysubstrate that includes a negative channel metal oxide semiconductor(nMOS) and/or a positive channel metal oxide semiconductor (pMOS)transistor and will eventually become a microelectronic device ormicroelectronic assembly.

As used herein, “suitability” for removing silicon nitride material froma microelectronic device having such nitride material thereoncorresponds to at least partial removal of silicon nitride material fromthe microelectronic device.

As used herein, “silicon nitride” and “Si₃N₄” correspond to pure siliconnitride (Si₃N₄) as well as impure silicon nitride including hydrogen,carbon and/or oxygen impurities in the crystal structure.

As used herein, “silicon oxide” refers to thin films made of siliconoxide (SiO_(x)), e.g., SiO₂, “thermal oxide” (ThO_(x)), and the like.The silicon oxide can be placed on the substrate by any method, such asby deposition via chemical vapor deposition from TEOS or another source,or by being thermally deposited. The silicon oxide generally contains acommercially useful low level of other materials or impurities. Thesilicon oxide may be present as part of a microelectronic devicesubstrate as a feature of the microelectronic device, for example as aninsulating layer.

As used herein, “at least partial removal of silicon nitride material”corresponds to the removal of at least a portion of the exposed siliconnitride layer. For example, partial removal of silicon nitride materialincludes the anisotropic removal of a silicon nitride layer thatcovers/protects the gate electrodes to form a Si₃N₄ sidewall. It is alsocontemplated herein that the compositions of the present invention maybe used more generally to substantially remove silicon nitride materialrelative to poly-silicon and/or silicon oxide layers. In thosecircumstances, “substantial removal” is defined in one embodiment as atleast 90%, in another embodiment at least 95%, and in yet anotherembodiment at least 99% of the silicon nitride material is removed usingthe compositions of the invention.

As used herein, “about” is intended to correspond to +/−5% of the statedvalue.

As used herein, “metal silicide” corresponds to any silicide includingthe species Ni, Pt, Co, Ta, Mo, W, and Ti, including but not limited toTiSi₂, NiSi, CoSi₂, NiPtSi, tantalum silicide, molybdenum silicide, andtungsten silicide.

“Silicic acid” is a general name for a family of chemical compounds ofsilicon, hydrogen, and oxygen, with the general formula[SiO_(x)(OH)_(4-2x)]_(n), and includes the compounds metasilicic acid((H₂SiO₃)_(n)), orthosilicic acid (H₄SiO₄), disilicic acid (H₂Si₂O₅),and pyrosilicic acid (H₆Si₂O₇). Silicic acid can be obtained in manyways well known to those skilled in the art, e.g. by hydrating finesilica powder (preferably 1 μm diameter or less), alkoxysilanes (e.g.,tetramethoxysilane (TMOS), tetraethoxysilane (TEOS),tetra-n-propoxysilane, tetra-n-butoxysilane), alkoxysilanes with aminogroups (e.g., aminotriethoxysilane, hexaethoxydisilazane), alkoxysilaneswith one or more halogen or pseudohalogen groups (e.g.,triethoxychlorosilane, triethoxyfluorosilane,triethoxy(isocyanato)silane, diethoxydichlorosilane), or combinationsthereof. For ease of reference, “alkoxysilane” will hereinafter be usedto include alkoxysilanes, alkoxysilanes with amino groups andalkoxysilanes with one or more halogen or pseudohalogen groups.

As described herein, the silicon oxide layer may be deposited from asilicon oxide precursor source, e.g., TEOS, or may be thermallydeposited silicon oxide. Other typical low-κ materials “low-k dielectricmaterial” corresponds to any material used as a dielectric material in alayered microelectronic device, wherein the material has a dielectricconstant less than about 3.5. In certain embodiments, the low-κdielectric materials include low-polarity materials such assilicon-containing organic polymers, silicon-containing hybridorganic/inorganic materials, organosilicate glass (OSG), TEOS,fluorinated silicate glass (FSG), silicon dioxide, silicon oxycarbide,silicon oxynitride, silicon nitride, carbon-doped oxide (CDO) orcarbon-doped glass, for example, CORAL™ from Novellus Systems, Inc.,BLACK DIAMOND™ from Applied Materials, Inc. (e.g., BD1, BD2, and BD3designations for PECVD) SiLK™ dielectric resins from Dow (polymers basedon crosslinked polyphenylenes by reaction of polyfunctionalcyclopentadienone and acetylene-containing materials; see, for example,U.S. Pat. No. 5,965,679, incorporated herein by reference), andNANOGLASS™ of Nanopore, Inc, (Silica aerogel/xerogel (known asnanoporous silica), and the like. It is to be appreciated that the low-κdielectric materials may have varying densities and varying porosities.

The compositions of the present invention must possess good metalcompatibility, e.g., a low etch rate on the interconnect metal and/orinterconnector metal silicide material. Metals of interest include, butare not limited to, copper, tungsten, cobalt, molybdenum, aluminum,tantalum, titanium and ruthenium. Silicides of interest include anysilicide including the species Ni, Pt, Co, Ta, Mo, W, and Ti, includingbut not limited to TiSi₂, NiSi, CoSi₂, NiPtSi, tantalum silicide,molybdenum silicide, and tungsten silicide.

Compositions of the invention may be embodied in a wide variety ofspecific formulations, as hereinafter more fully described.

In all such compositions, wherein specific components of the compositionare discussed in reference to weight percentage ranges including a zerolower limit, it will be understood that such components may be presentor absent in various specific embodiments of the composition, and thatin instances where such components are present, they may be present atconcentrations as low as 0.001 weight percent, based on the total weightof the composition in which such components are employed.

The composition includes aqueous phosphoric acid (e.g., concentratedphosphoric acid) in an amount that is effective to produce desiredetching of silicon nitride. The term “aqueous phosphoric acid” refers toan ingredient of the composition that is mixed or combined with otheringredients of the composition to form the composition. The term“phosphoric acid solids” refers to the non-aqueous component of anaqueous phosphoric acid ingredient, or of a composition that is preparedfrom aqueous phosphoric acid ingredient.

The amount of phosphoric acid solids contained in a composition can bean amount that, in combination with the other materials of an etchingcomposition, will provide desired etching performance, including desiredsilicon nitride etch rate and selectivity, which typically requires arelatively high amount (concentration) of phosphoric acid solids. Forexample, an etching composition can contain an amount of phosphoric acidsolids that is at least about 50 weight percent based on total weight ofthe composition, e.g., at least 70, or at least about 80 or 85 weightpercent phosphoric acid solids based on total weight of the composition.

To provide a desired amount of phosphoric acid solids, the compositionmay contain “concentrated” phosphoric acid as an ingredient that ismixed or combined with other ingredients (one ingredient optionallybeing water, in some form) to produce the composition. “Concentrated”phosphoric acid refers to an aqueous phosphoric acid ingredient thatcontains a high or maximum amount of phosphoric acid solids in thepresence of a low or minimum amount of water and substantially no otheringredients (e.g., less than 0.5 or 0.1 weight percent of any non-wateror non-phosphoric acid solids materials). Concentrated phosphoric acidcan typically be considered to have at least about 80 or 85 weightpercent phosphoric acid solids in about 15 or 20 weight percent water.Alternately, the composition may be considered to include an amount ofconcentrated phosphoric acid that is diluted with water, meaning forexample concentrated phosphoric acid that has been diluted with anamount of water before or after being combined with other ingredients ofthe etching composition, or an equivalent formed in any manner. Asanother alternative, an ingredient of the composition can beconcentrated phosphoric acid or a diluted phosphoric acid, and theetching composition can contain an additional amount of water that isprovided to the composition either as a component of a differentingredient or as a separate water ingredient.

As an example, if concentrated phosphoric acid is used to form thecomposition, the amount of concentrated phosphoric acid (85 weightpercent, in water) can be an amount that is at least 60, e.g., at least80 or at least 90, 93, 95, or at least 98 weight percent of thecomposition, based on total weight of the composition.

The compositions can comprise, consist of, or consist essentially of therecited ingredients and any combination of optional ingredients. As ageneral convention throughout the present description, the compositionas described, or an ingredient or component thereof, that is said to“consist essentially of” a group of specified ingredients or materialsrefers to a composition that contains the specified ingredients ormaterials with not more than a low or insignificant amount of otheringredients or materials, e.g., not more than 5, 2, 1, 0.5, 0.1, or 0.05parts by weight of other ingredients or materials. For example, acomposition that contains materials that consist essentially of: aqueousphosphoric acid, at least one silane compound chosen from (i) alkylaminoalkoxysilanes and (ii) alkylamino hydroxyl silanes, and a solventcomprising water, and optional ingredients as described, means acomposition that contains these ingredients and not more than 5, 2, 1,0.5, 0.1, or 0.05 parts by weight of any other dissolved or un-dissolvedmaterial or materials (individually or as a total) other than theidentified materials.

As used herein, “fluoride compound” corresponds to species includingionic fluoride ion (F⁻) or covalently bonded fluorine. It is to beappreciated that the fluoride species may be included as a fluoridespecies or generated in situ. In certain embodiments, this compoundcapable of generating the fluoride ion will be derived from HF,monoflurophosphoric (MFPA), difluorophosphoric (DFPA) orhexafluorophosphoric acid. In concentrated phosphoric acid compositions,HF will exist mostly in the form of monofluorophosphoric acid (MFPA). Incertain embodiments, the low-volatility MFPA or DFPA may be useddirectly in the compositions in order to simplify addition and blending.In other embodiments, the fluoride compound may be chosen from CsF andKF. In other embodiments, the fluoride compound may be chosen fromtetramethylammonium hexafluorophosphate; ammonium hexafluorophosphate;ammonium fluoride; ammonium bifluoride; quaternary ammoniumtetrafluoroborates and quaternary phosphonium tetrafluoroborates havingthe formula NR′₄BF₄ and PR′₄BF₄, respectively, wherein each R′ may bethe same as or different from one another and is chosen from hydrogen,straight-chained, branched, or cyclic C₁-C₆ alkyl (e.g., methyl, ethyl,propyl, butyl, pentyl, hexyl), and straight-chained or branched C₆-C₁₀aryl (e.g., benzyl); tetrabutylammonium tetrafluoroborate (TBA-BF₄); andcombinations thereof. In certain embodiments, the fluoride compound isselected from ammonium fluoride, ammonium bifluoride, quaternaryammonium tetrafluoroborates (e.g., tetramethylammoniumtetrafluoroborate, tetraethylammonium tetrafluoroborate,tetrapropylammonium tetrafluoroborate, tetrabutylammoniumtetrafluoroborate), quaternary phosphonium tetrafluoroborates, orcombinations thereof. In certain embodiments, the fluoride compoundcomprises ammonium bifluoride, ammonium fluoride, or a combinationthereof.

As used in the specification and the appended claims, the singular forms“a,” “an” and “the” include their plural referents unless the contextclearly dictates otherwise. The terms “containing” or “including” areintended to be synonymous with the term “comprising”, meaning that atleast the named compound, element, particle, or method step, etc., ispresent in the composition or article or method, but does not excludethe presence of other compounds, materials, particles, method steps,etc., even if the other such compounds, material, particles, methodsteps, etc., have the same function as what is named, unless expresslyexcluded in the claims.

In one aspect, the invention provides a composition comprising:

(a) phosphoric acid;

(b) at least one silane chosen from (i) alkylamino alkoxysilanes and(ii) alkylamino hydroxyl silanes, wherein said silane possesses at leastone moiety chosen from alkoxy, hydroxyl, and fluoro;

(c) a solvent comprising water; and optionally

(d) a fluoride compound, provided that the fluoride compound is otherthan hexafluorosilicic acid.

In certain embodiments, the phosphoric acid will be present in thecomposition in about 50 to about 95 weight percent. In otherembodiments, phosphoric acid will be present in about 70 to about 90weight percent, and in other embodiments, about 85 weight percent.

In certain embodiments of the invention, the composition may furthercomprise a fluoride compound. In one embodiment, the fluoride compoundis selected from HF and monofluoro phosphoric acid. In otherembodiments, the fluoride compound is selected from cesium fluoride andpotassium fluoride. In other embodiments, the fluoride compound isselected from ammonium hexafluorophosphate; tetramethylammoniumhexafluorophosphate; ammonium fluoride; ammonium bifluoride; fluoroboricacid; quaternary ammonium tetrafluoroborates and quaternary phosphoniumtetrafluoroborates having the formula NR′₄BF₄ and PR′₄BF₄, respectively,wherein R′ may be the same as or different from one another and isselected from hydrogen, straight-chained, branched, or cyclic C₁-C₆alkyl, and straight-chained or branched C₆-C₁₀ aryl; tetramethylammoniumtetrafluoroborate (TMA-BF₄); and combinations thereof.

In certain embodiments, the alkylamino alkoxysilane and alkylaminohydroxyl silane compounds are represented by the formula

wherein each X is independently chosen from fluorine, a C₁-C₈ alkylgroup, or a group of the formula —OR, wherein R is hydrogen or a C₁-C₈alkyl group, n is an integer of from 1 to 6, and each R¹ isindependently chosen from hydrogen, a C₁-C₈ alkyl group, or a group ofthe formula C₁-C₈ alkoxy (CH₂)_(n)—. In certain embodiments, thealkylamino alkoxysilane and alkylamino hydroxyl silane compounds arechosen from (3-aminopropyl)triethoxy silane (CAS No. 919-30-2);(3-aminopropyl)silane triol (CAS No. 58160-99-9);3-aminopropyldimethylethoxysilane (CAS No. 18306-79-1);3-aminopropylmethyldiethoxysilane (CAS No. 3179-76-8); andN-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane (CAS No. 3069-29-2);(N,N-dimethyl-3-aminopropyl)trimethoxysilane, (CAS No. 2530-86-1); and3-aminopropyldimethylfluorosilane (CAS No. 153487-58-2).

In certain embodiments, the alkylamino alkoxysilane and alkylaminohydroxyl silane compounds are represented by the formula

wherein each X is independently chosen from fluorine, a C₁-C₈ alkylgroup, or a group of the formula —OR, wherein R is hydrogen or a C₁-C₈alkyl group, n is an integer of from 1 to 6, y is an integer of from 1to 6, and wherein z is an integer of from 1 to 6.

In certain embodiments, the alkylamino alkoxysilane and alkylaminohydroxyl silane compounds are chosen fromN-(3-trimethoxysilylpropyl)diethylenetriamine (CAS Number 35141-30-1);N-(2-aminoethyl)-3-aminopropyltriethoxy silane (CAS No. 5089-72-5);N-(2-aminoethyl)-3-aminopropyl silane triol (CAS No. 1760-24-3);(3-trimethoxysilylpropyl)dethylenetriamine (CAS No. 35141-30-1); andN-(6-aminohexyl)aminopropyltrimethoxysilane (CAS No. 51895-58-0).

In certain embodiments, two alkylamino groups are connected to a siliconatom that carries two X groups (as defined above) or one X and one alkylgroup, e.g. 3,3′-(dimethoxysilylene)bis-(1-Propanamine) (CAS No.51749-36-1):

In certain embodiments, one or more aminoalkyl groups branch out of analkyl or aminoalkyl chain that is connected to a silicon atom thatcarries three X groups (as defined above) or two X and one alkyl group,e.g. 2-[(Dimethoxymethylsilyl)methyl]-1,4-butanediamine (CAS No.1019109-96-6):

In certain embodiments, two or more silicon atoms connected by oxygenbridges carry a total of at least one aminoalkyl group and at least one“X” group as described above, with the remaining silicon substituentsbeing alkylamine, “X”, or alkyl; e.g.1,3-Bis(3-aminopropyl)-1,1,3,3-tetraethoxydisiloxane (CAS No.17907-78-7):

and its methoxy analog,1,3-Bis(3-aminopropyl)-1,1,3,3-tetramethoxydisiloxane (CAS No.76712-65-7):

The amount of the alkylamino alkoxysilane and alkylamino hydroxyl silanecompounds in the compositions of the invention can be an amount that, incombination with the other materials of an etching composition, willprovide desired etching performance, including desired silicon nitrideetch rate and selectivity. For example, an etching composition cancontain an amount of alkylamino alkoxysilane and alkylamino hydroxylsilane compounds, which may be a single species or a combination of twoor more species, in a range from about 20 to 10,000 parts per million(i.e., from 0.0020 to 1.0 weight percent) based on total weight of thecomposition, or from about 20 to 2,000, 4,000, or 5,000 parts permillion (i.e., from 0.002 to 0.2, 0.4, or 0.5 weight percent) based ontotal weight of the composition.

Component (c) is a solvent comprising water. Optionally, the solvent mayfurther comprise one or more water-miscible solvents such aspyrrolidinones, glycols, amines, and glycol ethers, including, but notlimited to, methanol, ethanol, isopropanol, butanol, and higher alcohols(such as C₂-C₄ diols and C₃-C₄ triols), tetrahydrofurfuryl alcohol(THFA), halogenated alcohols (such as 3-chloro-1,2-propanediol,1-chloro-2-propanol, 2-chloro-1-propanol, 3-chloro-1-propanol,3-bromo-1,2-propanediol, 1-bromo-2-propanol, 3-bromo-1-propanol,3-iodo-1-propanol, 4-chloro-1-butanol, 2-chloroethanol), acetic acid,propionic acid, trifluoroacetic acid, N-methylpyrrolidinone (NMP),cyclohexylpyrrolidinone, N-octylpyrrolidinone, N-phenylpyrrolidinone,methyldiethanolamine, dimethyl formamide (DMF), dimethylsulfoxide(DMSO), tetramethylene sulfone (sulfolane), phenoxy-2-propanol (PPh),propriophenone, ethyl lactate, ethyl acetate, ethyl benzoate,acetonitrile, ethylene glycol, propylene glycol (PG), 1,3-propanediol,butyryl lactone, butylene carbonate, ethylene carbonate, propylenecarbonate, dipropylene glycol, diethylene glycol monomethyl ether,triethylene glycol monomethyl ether, diethylene glycol monoethyl ether,triethylene glycol monoethyl ether, ethylene glycol monopropyl ether,ethylene glycol monobutyl ether, diethylene glycol monobutyl ether(i.e., butyl carbitol), triethylene glycol monobutyl ether, ethyleneglycol monohexyl ether, diethylene glycol monohexyl ether, ethyleneglycol phenyl ether, propylene glycol methyl ether, dipropylene glycolmethyl ether (DPGME), tripropylene glycol methyl ether (TPGME),dipropylene glycol dimethyl ether, dipropylene glycol ethyl ether,propylene glycol n-propyl ether, dipropylene glycol n-propyl ether(DPGPE), tripropylene glycol n-propyl ether, propylene glycol n-butylether, dipropylene glycol n-butyl ether, tripropylene glycol n-butylether, propylene glycol phenyl ether, dipropylene glycol methyl etheracetate, tetraethylene glycol dimethyl ether (TEGDE), dibasic ester,glycerine carbonate, N-formyl morpholine, triethyl phosphate, andcombinations thereof. When using an alkoxysilane additive, itshydrolysis generates a small amount of alcohol, for example, methanol orethanol, which is incorporated into the formulation as the alcoholitself or as its phosphoric acid monoester and is mostly boiled off attypical process temperatures. In addition, the organic solvent maycomprise other amphiphilic species, i.e., species that contain bothhydrophilic and hydrophobic moieties similar to surfactants.

In certain embodiments, the compositions of the invention furthercomprise low molecular weight amines and amine phosphate salts. In otherembodiments, the low molecular weight amines and amine phosphate saltsare primary, secondary, or tertiary C₁-C₆ alkylamine or phosphate saltsthereof. Examples include dimethylamine, trimethylamine, triethylamine,tripropylamine, tributylamine and the like. It will be appreciated thatwhen such amines or their aqueous solutions are added to a concentratedH₃PO₄ composition, amine phosphate salts will form.

In one embodiment, the composition comprises: (a) phosphoric acid; (b)N-(2-aminoethyl)-3-aminopropyl silanetriol; and (c) a solvent comprisingwater. In a further embodiment, the composition further comprises HF ormonofluorophosphoric acid. In a further embodiment, the compositionfurther comprises triethylamine or a dihydrogen phosphate salt thereof.

The composition may optionally comprise surfactant(s) (different fromthe other optional or required ingredients of the present description)to improve performance of the composition. As used herein the term“surfactant” refers to an organic compound that lowers the surfacetension (or interfacial tension) between two liquids or between a liquidand a solid, typically an organic amphiphilic compound that contains ahydrophobic group (e.g., a hydrocarbon (e.g., alkyl) “tail”) and ahydrophilic group. Preferred surfactants are thermally stable and stayionic under strongly acidic conditions such as the conditions of anetching process of the present invention. Examples includeperfluoroalkylsulfonic acids and long-chain quaternary ammoniumcompounds (e.g. dodecyltrimethylammonium hydrogen sulfate). Fluorinatednon-ionic surfactants such as Chemours' Capstone® FS-31/FS-35 can alsobe used. Non-ionic unfluorinated surfactants such as poly(ethyleneglycol)-poly(propylene glycol) copolymers (“PEG-PPG”) can also be used,and are better suited for lower-acidity compositions (e.g. ≤75% H₃PO₄)and operation at ≤130° C.

The amount of surfactant in the composition can be an amount that, incombination with the other materials of an etching composition, willprovide desired overall performance. For example, the composition cancontain an amount of surfactant that may be in a range from about 0.001to about 10 weight percent, e.g., from about 0.01 to about 0.5, 1, 2, 7,or 7 weight percent surfactant based on total weight of the composition.

Optionally, the compositions can contain an amount of carboxylic acidcompound, meaning an organic compound that contains at least onecarboxylic acid group. According to the invention, the presence of acarboxylic acid compound in composition as described can improveperformance by inhibiting redeposition of silicon oxide or formation ofparticles of the same. In certain embodiments, the carboxylic acidcompounds for use in the compositions include acetic acid, malonic acid,succinic acid, 2-methylsuccinic acid, glutaric acid, adipic acid,salicylic acid, 1,2,3-propanetricarboxylic acid (a.k.a. tricarballylicacid), 2-phosphonoacetic acid, 3-phosphonopropanoic acid, and2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA), any of which may beused alone, in combination together with each other, or in combinationwith a different carboxylic acid compound.

The amount of carboxylic acid compound (including derivatives thereof)contained in the compositions can be an amount that, in combination withthe other materials of the compositions, will provide desired etchingperformance while not otherwise affecting performance or chemicalstability of an etching composition. For example, the compositions cancontain an amount of carboxylic acid compound, which may be a singlespecies or a combination of two or more species, in a range from about0.01 to about 10 weight percent based on total weight of thecomposition, or from about 0.1 to about 5 or 8 weight percent based ontotal weight of the composition.

The composition may contain water from one or from multiple sources. Forexample, water will be present in an aqueous phosphoric acid ingredient.Additionally, water may be used as a carrier for one or more of theother ingredients of the etching composition, and water may be addedalone as its own ingredient. The amount of water should be sufficientlylow to allow the composition to exhibit desired or preferred oradvantageous etching performance properties, including a useful(sufficiently high) silicon nitride etch rate. An increase in thepresence of water tends to increase the etch rate of silicon nitride butcan also depress the boiling point of the etching composition, whichforces a reduction in operating temperature of the etching compositionand an opposite effect. Examples of amounts of water, from all sources,in an etching composition, can be less than about 50, 40, or 30 weightpercent, for example in a range from about 5 weight percent to about 25percent by weight, based on total weight of the composition, or in arange from about 10 to 20 weight percent water based on total weight ofthe composition.

Optionally, these and other example compositions as described cancontain, consist of, or consist essentially of the phosphoric acid, theamino hydroxyl silane or amino alkoxy silane, and any one or anycombination of the identified optional ingredients. Certain embodimentsof the compositions of the invention do not require and may excludeother types of ingredients not typically included in an etchingcomposition, such as a pH adjusting agent (other than the acidsmentioned as potential ingredients herein) and solid materials such asabrasive particles.

The following table contains illustrative compositions in weight percentbelieved to be useful in the practice of the invention:

Example H₃PO₄ Solubilizer Active fluoride DIW Amine Total 1 71% APST, 1%HF, 0.2% 12.8% Dimethylamine, 100% 15% 2 76% N2APST, 1.5% 0 12.3%Trimethylamine, 100% 10% 3 74.4%   APST, 3% NH4F, 0.2% 22.4% 0 100% 478% N3APTMS, Triethylamine 18.5% 0 100% 3% trihydrofluoride, 0.5% 582.5%   APST, 1.2% 3-aminopropyl-   16% 0 100% dimethylfluorosilane 0.3%6 78% N2APST, 2% MFPA, 0.5%   19% Triethylamine 100% dihydrogenphosphate (TEAP), 0.5   7 65% APTES, 2% 0   32% TEAP, 1%  100% 8 80%APTES, 1.25% Tetramethylammonium 18.3%  TEAP, 0.3% 100%hexafluorophosphate, 0.15%  9 81.1%   DMSBP, 2% HF, 0.2% 13.7%Dipropylamine, 3% 100% 10 82.2%   BAPTEDS, 0 14.8% 0 3% 11 62% AHAPTMS,Tetramethylammonium 26.8% 0 100% 3% hexafluorophosphate, DIW, 0.2%   8%BC

As used herein, the following shorthand references are made:

(3-aminopropyl)triethoxy-silane (CAS No. 919-30-2) “APTES”;

(3-aminopropyl)silane triol (CAS No. 58160-99-9) “APST”;

N-(2-aminoethyl)-3-aminopropyl silane triol (CAS No. 1760-24-3)“N2APST”;

N¹-(3-Trimethoxysilypropyl)diethylenetriamine) “N3APTMS”;

3,3′-(dimethoxysilylene)bis-(1-Propanamine) (CAS No. 51749-36-1)“DMSBP”;

1,3-Bis(3-aminopropyl)-1,1,3,3-tetraethoxydisiloxane (CAS No.17907-78-7) “BAPTEDS”;

N-(6-aminohexyl)aminopropyltrimethoxysilane (CAS No. 51895-58-0)“AHAPTMS”; and

diethylene glycol monobutyl ether (butyl carbitol) “BC”.

In yet another aspect, the invention provides a method for removingsilicon nitride from a microelectronic device, said method comprisingcontacting the microelectronic device with a composition of the presentinvention, for sufficient time under sufficient conditions to at leastpartially remove said silicon nitride material from the microelectronicdevice. For example, silicon nitride material may be removed withoutsubstantially damaging metal and metal silicide interconnect materials.The invention thus provides methods for selectively and substantiallyremoving silicon nitride materials relative to polysilicon and/orsilicon oxide materials from the surface of the microelectronic devicehaving same thereon using the compositions described herein. The metalsilicide materials that are present are not substantially corroded bysaid removal compositions using said method.

In etching application, the composition is applied in any suitablemanner to the surface of the microelectronic device having the siliconnitride material thereon, e.g., by spraying the removal composition onthe surface of the device, by dipping (in a static or dynamic volume ofthe removal composition) of the device including the silicon nitridematerial, by contacting the device with another material, e.g., a pad,or fibrous sorbent applicator element, that has the removal compositionabsorbed thereon, by contacting the device including the silicon nitridematerial with a circulating removal composition, or by any othersuitable means, manner or technique, by which the removal composition isbrought into removal contact with the silicon nitride material. Theapplication may be in a batch or single wafer apparatus, for dynamic orstatic cleaning. In one embodiment, the application of the removalcomposition to the surface of the microelectronic device is controlledagitation whereby the composition is circulated through the containerhousing said composition.

The compositions of the present invention, by virtue of theirselectivity for silicon nitride material relative to other materialsthat may be present on the microelectronic device structure and exposedto the composition, such as metallization, polysilicon, siliconoxide(s), etc., achieve at least partial removal of the silicon nitridematerial in a highly efficient and highly selective manner.

In use of the compositions of the invention for removing silicon nitridematerial from microelectronic device structures having same thereon, thecomposition typically is contacted with the microelectronic devicestructure for a sufficient time of from about 1 minute to about 200minutes, in one embodiment, about 15 minutes to about 100 minutes, orabout 1 minute to about 3 minutes for a single wafer tool, at sufficientconditions including, but not limited to, in one embodiment, atemperature in a range of from about 120° C. to about 180° C. Suchcontacting times and temperatures are illustrative, and any othersuitable time and temperature conditions may be employed that areefficacious to at least partially remove the silicon nitride materialfrom the device structure, within the practice of the invention.

Following the achievement of the desired removal action, the removalcomposition is readily removed from the microelectronic device to whichit has previously been applied, e.g., by rinse, wash, or other removalstep(s), as may be desired and efficacious in a given end useapplication of the compositions of the present invention. For example,the device may be rinsed with a rinse solution including deionized waterand/or dried (e.g., spin-dry, N₂, vapor-dry, etc.).

The removal compositions of the invention selectively etch siliconnitride material relative to poly-Si and silicon oxides from the surfaceof the microelectronic device without causing substantial corrosion ofthe metal and/or metal silicide interconnect material(s). For example,the selectivity of silicon nitride to silicon oxide(s) in the presenceof the removal compositions of the invention are, in one embodiment, ina range from about 10:1 to about 7,000:1, in another embodiment about30:1 to about 3,000:1, and in another embodiment about 100:1 to about2000:1 at temperatures of 40-100° C. in one embodiment, of 60-95° C. inanother embodiment, and of 75-90° C. in yet another embodiment. When thesilicic acid source includes an alkoxysilane, e.g., TEOS, theselectivity of silicon nitride relative to silicon oxide(s) can be tunedfrom about 20:1 to infinity in one embodiment and in the range fromabout 20:1 to about 7,000:1 in another embodiment. In fact, theselectivity is formally negative for some usable formulations,reflecting the fact that the thickness of the oxide film is veryslightly but measurably increased by precipitation of silica.

An etching step of the present description can be useful to etch siliconnitride material from a surface of any type of substrate. According toparticular embodiments, a substrate can include alternating thin filmlayers of silicon nitride as structural features of a substrate thatincludes alternating thin film layers of the silicon nitride layers withsilicon oxide. The silicon oxide layers are high aspect ratio structuresthat contain the silicon nitride layers disposed between the layers ofsilicon oxide.

A still further aspect of the invention relates to methods ofmanufacturing an article comprising a microelectronic device, saidmethod comprising contacting the microelectronic device with thecompositions of the present invention for sufficient time to etchinglyremove silicon nitride material from the surface of the microelectronicdevice having same thereon, and incorporating said microelectronicdevice into said article.

The compositions described herein are easily formulated by simpleaddition of the respective ingredients and mixing to homogeneouscondition. Furthermore, the compositions may be readily formulated assingle-package formulations or multi-part formulations that are mixed atthe point of use, preferably multi-part formulations. The individualparts of the multi-part formulation may be mixed at the tool or in astorage tank upstream of the tool. The concentrations of the respectiveingredients may be widely varied in specific multiples of thecomposition, i.e., more dilute or more concentrated, and it will beappreciated that the compositions described herein can variously andalternatively comprise, consist or consist essentially of anycombination of ingredients consistent with the disclosure herein.

Another aspect of the invention relates to a kit including, in one ormore containers, one or more components adapted to form the compositionsdescribed herein. In one embodiment, the kit includes, in one or morecontainers, the combination of at least one of components (a)-(c) abovefor combining with water at the fab or the point of use. The containersof the kit must be suitable for storing and shipping said cleaningcomposition components, for example, NOWPak®. containers (AdvancedTechnology Materials, Inc., Danbury, Conn., USA). The one or morecontainers which contain the components of the first cleaningcomposition preferably include means for bringing the components in saidone or more containers in fluid communication for blending and dispense.For example, referring to the NOWPak®. containers, gas pressure may beapplied to the outside of a liner in said one or more containers tocause at least a portion of the contents of the liner to be dischargedand hence enable fluid communication for blending and dispense.Alternatively, gas pressure may be applied to the head space of aconventional pressurizable container or a pump may be used to enablefluid communication. In addition, the system preferably includes adispensing port for dispensing the blended cleaning composition to aprocess tool.

Substantially chemically inert, impurity-free, flexible and resilientpolymeric film materials, such as high density polyethylene, may be usedto fabricate the liners for said one or more containers. Desirable linermaterials are processed without requiring co-extrusion or barrierlayers, and without any pigments, UV inhibitors, or processing agentsthat may adversely affect the purity requirements for components to bedisposed in the liner. A listing of desirable liner materials includefilms comprising virgin (additive-free) polyethylene, virginpolytetrafluoroethylene (PTFE), polypropylene, polyurethane,polyvinylidene chloride, polyvinylchloride, polyacetal, polystyrene,polyacrylonitrile, polybutylene, and so on. Exemplary thicknesses ofsuch liner materials are in a range from about 5 mils (0.005 inch) toabout 30 mils (0.030 inch), as for example a thickness of 20 mils (0.020inch).

Regarding the containers for the kits, the disclosures of the followingpatents and patent applications are hereby incorporated herein byreference in their respective entireties: U.S. Pat. No. 7,188,644entitled “APPARATUS AND METHOD FOR MINIMIZING THE GENERATION OFPARTICLES IN ULTRAPURE LIQUIDS;” U.S. Pat. No. 6,698,619 entitled“RETURNABLE AND REUSABLE, BAG-IN-DRUM FLUID STORAGE AND DISPENSINGCONTAINER SYSTEM;” and U.S. Patent Application No. 60/916,966 entitled“SYSTEMS AND METHODS FOR MATERIAL BLENDING AND DISTRIBUTION” filed onMay 9, 2007 in the name of John E. Q. Hughes, and PCT/US08/63276entitled “SYSTEMS AND METHODS FOR MATERIAL BLENDING AND DISTRIBUTION”filed on May 9, 2008 in the name of Advanced Technology Materials, Inc.

Accordingly, in a further aspect, the invention provides a kitcomprising one or more containers having components therein suitable forremoving silicon nitride from a microelectronic device, wherein one ormore containers of said kit contains (a) phosphoric acid; (b) at leastone silane compound chosen from (i) alkylamino alkoxysilanes and (ii)alkylamino hydroxyl silanes as described herein; and (c) a solventcomprising water; and optionally (d) a fluoride compound, provided thatthe fluoride compound is other than hexafluoro silicic acid.

This invention can be further illustrated by the following examples ofcertain embodiments thereof, although it will be understood that theseexamples are included merely for purposes of illustration and are notintended to limit the scope of the invention unless otherwisespecifically indicated.

Examples

High aspect ratio structures were processed to first remove any oxidizedfilm from the exposed silicon nitride. Structures were then processed inthe formulation at the desired temperature in a boiling flask withstirring. For the conditions where silicate loading is specified eithertetramethylammonium silicate (TMAS) or silica nanoparticles were added.For examples 16 and 17, TMAS was used and the loading is provided as ppmSi. For all other examples Sift nanoparticles were used and silicateloading is provided as ppm SiO₂. Structures were processed for timeslong enough to fully remove the SiN, typically between 45 minutes and 2hours. After processing in the formulation structures were rinsed in hotdeionized water and dried with flowing nitrogen. The etch rates shownwere similarly obtained by processing blanket films, with thicknessmeasured by spectroscopic ellipsometry.

TABLE 1 FORMULATION EXAMPLES (Weight Percent, balance ~85% H₃PO₄)Example

 / additive 

HF APST N2APST N3APTMS TEAP 12 0.0025 0.07 0.02 13 0.02 14 0.0025 0.040.02 15 0.04 0.02 16 0.002 0.09 17 0.002 0.07 18 0.002 1.4 0.2Acronyms have the same meaning as for examples 1-11 above.

TABLE 2 Post-etch excess thickness (deposit build-up) of oxide instructure, as a function of added SiO₂ in the formulation (at 152° C.) 0ppm 50 ppm 100 ppm 150 ppm 200 ppm Example SiO₂ SiO₂ SiO₂ SiO₂ SiO₂ 12OK* OK OK OK OK 13 OK OK OK OK OK 14 OK OK 85% OK >2 nm >15 nm H₃PO₄*”OK” signifies a change of <2 nm relative to the initial oxidethickness.

TABLE 3 Etch rates (ER) as a function of added SiO₂ (at 152° C.) Example0 ppm 50 ppm 100 ppm 150 ppm 200 ppm 13 SiO₂ SiO₂ SiO₂ SiO₂ SiO₂ SiN ER36 34 35 34 36 (A/min) ThOx ER 0.3 −0.1 −0.1 −0.2 −0.2 (A/min) 85% H₃PO₄SiN ER 41 35 34 (A/min) ThOx ER 1.0 0.1 0.1 (A/min)Note that, compared with examples 12-14, 85% H₃PO₄ either has poorselectivity toward oxide (about 40:1 at 0 ppm silica, Table 3) or causesexcessive oxide redeposition (at 100 and 200 ppm silica, Table 2).

TABLE 4 Performance Summary of Formulations 16 and 17: 3D NAND SiNSelective Etches Example 85% Example 18 + Critical H3PO4/15% H2O +Example 16 + 80 17 + 45 45 ppm requirements Target [Si] = 40 ppm ppm Sippm Si Si SiNx:SiO2 1000:1 830:1 >3000:1 2300:1 >:2000:1 SelectivitySiNx Removal >12 12.5 14.6 14.5 12.5 Rate nm/min Loading window >0 ppmno window 15-80 ppm 35-45 ppm 45->224 (loading with Si Si Si ppmselectivity >1000 & no re-deposition) Bath Life <10% √ stable ER stableER stable ER Stability Change >24 hrs >24 hrs >24 hrs Shelf Life in ER√ >2 years >2 years >2 years Stability (Bath Loading Stability life √ NoER No ER Not >24 hrs, change, no- change, no- measured Shelf liferedeposition redeposition ≥6 with with months) bleed/feed bleed/feedTemperature <160° C. 150° C. 150° C. 150° C. 150° C. (° C.)Addition of dissolved silicates during processing reduces silicon oxideetch rates without substantially changing nitride etch rate.At high enough dissolved silicate concentration a silica-richprecipitate is redeposited on SiO₂ surfaces within the 3D NANDstructure.The loading window is defined in this case on the low end by whereselectivity is >1000 and on the high end by the onset of redeposition. Adifferent selectivity target will result in a different width of theloading window.

We claim:
 1. A composition consisting of: (a) phosphoric acid; (b) atleast one silane chosen from (i) alkylamino alkoxysilanes and (ii)alkylamino hydroxyl silanes, wherein said silane possesses at least onemoiety chosen from alkoxy, hydroxyl, and fluoro; (c) a solventcomprising water; and optionally (d) a fluoride compound, provided thatthe fluoride compound is other than hexafluoro silicic acid; (e) analkyl amine or phosphate salt thereof (f) a surfactant, (g) a carboxylicacid compound, or (h) a dissolved silicate.
 2. The composition of claim1, wherein the phosphoric acid is present in a range of 50 to 95 weightpercent, based on the total weight of the composition.
 3. Thecomposition of claim 1, wherein the fluoride compound is present and ischosen from HF and monofluorophosphoric acid.
 4. The composition ofclaim 1, wherein the fluoride compound is present and is a chosen fromcesium fluoride and potassium fluoride.
 5. The composition of claim 1,wherein the fluoride compound is present and is chosen from fluoroboricacid; tetramethylammonium hexafluorophosphate; ammonium fluoride;ammonium bifluoride; quaternary ammonium tetrafluoroborates andquaternary phosphonium tetrafluoroborates having the formula NR′₄BF₄ andPR′₄BF₄, respectively, wherein R′ may be the same as or different fromone another and is selected from hydrogen, straight-chained, branched,or cyclic C₁-C₆ alkyl, and straight-chained or branched C₆-C₁₀ aryl;tetrabutylammonium tetrafluoroborate (TBA-BF₄); and combinationsthereof.
 6. The composition of claim 1, wherein the alkylaminoalkoxysilane and alkylamino hydroxyl silane compounds are represented bythe formula

wherein each X is independently chosen from fluorine, a C₁-C₈ alkylgroup, or a group of the formula —OR, wherein R is hydrogen or a C₁-C₈alkyl group, n is an integer of from 1 to 6, and each R¹ isindependently chosen from hydrogen, a C₁-C₈ alkyl group, or a group ofthe formula C₁-C₈ alkoxy(CH₂)_(n)—.
 7. The composition of claim 6,wherein R is methyl or ethyl.
 8. The composition of claim 6, wherein thealkylamino alkoxysilane and alkylamino hydroxyl silane compounds arechosen from (3-aminopropyl)triethoxy-silane;(3-aminopropyl)silane-triol; 3-aminopropyldimethylethoxysilane;3-aminopropylmethyldiethoxysilane; andN-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane;(N,N-dimethyl-3-aminopropyl)trimethoxysilane; and3-aminopropyldimethylfluorosilane.
 9. The composition of claim 1,wherein the alkyl amine or phosphate salt thereof is present and ischosen from a primary, secondary, or tertiary C₁-C₆ alkylamine ordihydrogen phosphate salt thereof.
 10. The composition of claim 1,wherein the alkylamino alkoxysilane and alkylamino hydroxyl silanecompounds are represented by the formula

wherein each X is independently chosen from fluorine, a C₁-C₈ alkylgroup, or a group of the formula —OR, wherein R is hydrogen or a C₁-C₈alkyl group, n is an integer of from 1 to 6, y is an integer of from 1to 6, and wherein z is an integer of from 1 to
 6. 11. The composition ofclaim 10, wherein R is methyl or ethyl.
 12. The composition of claim 10,wherein the alkylamino alkoxysilane and alkylamino hydroxyl silanecompounds are chosen from N-(3-trimethoxysilylpropyl)diethylenetriamine;N-(2-aminoethyl)-3-aminopropyltriethoxy silane;N-(2-aminoethyl)-3-aminopropyl-silane triol;(3-trimethoxysilylpropyl)dethylenetriamine; andN-(6-aminohexyl)aminopropyltrimethoxysilane.
 13. The composition ofclaim 10, wherein the alkyl amine or phosphate salt thereof is presentand is chosen from a primary, secondary, or tertiary C₁-C₆ alkylamine ordihydrogen phosphate salt thereof.
 14. A method for removing siliconnitride from a microelectronic device, said method comprising contactingthe microelectronic device with a composition of claim 1, for sufficienttime under sufficient conditions to at least partially remove saidsilicon nitride material from the microelectronic device.
 15. Thecomposition of claim 1, wherein the alkylamino alkoxysilane andalkylamino hydroxyl silane compounds are represented by the formula


16. The composition of claim 1, wherein the alkylamino alkoxysilane andalkylamino hydroxyl silane compounds are represented by the formula


17. The composition of claim 1, wherein the alkylamino alkoxysilane andalkylamino hydroxyl silane compounds are represented by formula (I) or(II)


18. A composition consisting of: (a) phosphoric acid; (b)N-(2-aminoethyl)-3-aminopropyl-silane-triol or (3-aminopropyl)silanetriol; (c) a solvent comprising water, and optionally (d) a fluoridecompound, provided that the fluoride compound is other than hexafluorosilicic acid; (e) an alkyl amine or phosphate salt thereof (f) asurfactant, (g) a carboxylic acid compound, or (h) a dissolved silicate.19. The composition of claim 18, wherein the fluoride compound ispresent and is chosen from HF or monofluorophosphoric acid.
 20. Thecomposition of claim 18, wherein the alkyl amine or phosphate saltthereof is present and is chosen from triethylamine or a dihydrogenphosphate salt thereof.